The good news is that the ATK LQ models come stock with some
of the finest hardware you'll find anywhere, short of a factory works racer.
Additionally, ATK will practically custom build the bike for a particular
customer, adding or removing options to suit, swapping gearing or tires, etc.
This impressive list of trick features includes Talon billet hubs front and
rear, DID O-ring chain, Talon/Answer Radialite rear sprocket, Pro Taper
handlebars, the latest WP fork with high and low speed compression damping, WP
rear shock, shroudless 3.1 gallon fuel cell, machined billet triple clamps,
quality Dunlop tires front and rear, and an innovative vacuum-actuated,
adjustable power valve.

While the ATK literally reeks of quality custom hardware, it unfortunately has
its share of warts too. For the most part, these are features that basically
require further "refinement" to improve performance and longevity. Near the top
of that list is the thin gage steel used on the frame (for tabs, gussets, etc.)
and swing arm. This allows many mountings (fenders, side covers, etc.) to flex
or bend out of shape, giving the bike an overall weak and vulnerable look. Older
ATKs used to come with trick-looking utilitarian chromoly swing arms--what
happened? Speaking of vulnerable, the pipe sticks out like a neglected hernia to
the front and right side of the motor, begging to be mashed. Similarly, the
chain guide is a disaster waiting to happen, constructed from thin gage aluminum
that won't stand up to hard pack ruts, let alone rocks. For the most part,
everything can be fixed, its just a matter of deciding where to start.

The Rotax powerplant is slightly under square with a 69.8mm stroke and 67.75mm
bore (67.5mm for the 250). Straight from Utah, the motor starts easily in spite
of a smallish 125 sized kickstarter and quickly achieves a nice steady idle. The
head has an integral thermostat, facilitating motor warm-up. The motor uses a
Mikuni TMS 38mm carburetor, which is the pilot-less model that surfaced some
years back. Factory jetting uses a 350 main, the double tapered 6DGY4-56 needle
with the clip in the #2 position, a "G" slide, and the air screw set 1.5 turns
out.

The motor employs a vacuum-actuated adjustable power valve that uses exhaust gas
pressure against a variable spring tension to effect valve opening timing. An
external plastic cover located just above the head pipe permits the adjustment,
using a threaded plastic plug that can increase or decrease the spring tension.
Standard position is with the adjuster nut flush with the power valve cover,
with two full turns of adjustment possible in either direction from the standard
(flush) position. Turning the adjuster out decreases the spring tension holding
the valve closed, thus allowing the power valve to open sooner. Conversely,
turning the adjuster in increases spring tension and holds the power valve
closed longer.

With the above jetting and the power valve in the standard position, the motor
is a real sleeper, with practically no grunt off the bottom, a decent midrange
and fair top end runout. The lack of bottom end was really frustrating in
high-traction sand conditions, as the motor resisted getting into the more
powerful midrange, despite repeated clutch feathering. Like lower horse power
bikes (read: 125s), proper gear selection was imperative.

For rocks and the slick stuff, this is it; this is the bike. Most agree,
however, that South Jersey sand will still demand a little more punch. We're at
odds where to proceed next, however, the engine's specs list a seven to one
compression ration for the Rotax powerplant, significantly lower than most other
dirt two strokes.

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